Effect of Root Age and Day-Length Extension on Sugar Beet Floral Induction and Fertility

Abstract

Bolting tendency in the crop species Beta vulgaris, which includes the sugar beet, is a complex trait governed by various environmental cues, including prolonged periods of cold temperatures over winter (vernalization) and photoperiod. This work was carried out as a part of a series of experiments on sugar beet floral induction under Egyptian conditions as part of the effort to breed and select sugar beet cultivars adapted to local environmental conditions. Ten diploid cultivars were sown in the field at three dates on 15th, 30th July and 15th August to provide roots at the ages of 120, 135 and 150 days, and harvested on the 15th of December. The roots were vernalized at 4°C for 45 days before replanting in the field. Extended vs. natural day-length were applied 3 weeks after replanting. Data was collected on flowering behavior, pollen fertility seed setting and seed germination. The results indicate that cultivars’ responses are the main factor that controlled the response to the imposed treatments. The response of cultivars varied according to root age, and day-length treatments. In most of the flowering cultivars, extended day-length improved the measured traits. Older root age also tended to enhance the measured traits with minor exceptions. The findings of this work are a step towards the definition of techniques that can be used to start a sugar beet breeding program under Egyptian conditions.